If you aren't giving your body enough calories with your eating habits & extreme exercise, your body can go into "starvation mode" and try to hang on to the fat storage to protect itself from starvation.  I'd count how many calories you are taking in and try to up it some, if you are doing low carb & meat, try adding a handfull of nuts, they will give you healthy protein & healthy fat, and they will add a couple hundred calories to your diet, hopefully making your body understand that you aren't starving and that you'd like to lose those last pounds.  Have you used a BMI calculator?  With your height & weight, I don't think you'd have much to lose.